Catalytic oxidation of naphthalene



I Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE ALIPHONS O. JAEGEB,OI GRAFTON, PENNSYLVANIA, ASSIGNOR TO TH]! SELDEH' GOI- PANY, OFPITTSBURGH, PENNSYLVANIA, A CORPORATION 01' DELAWARE CATALYTIC OXIDATIONOF NAPHTHALIENE 3N0 Drawing. Original application filed August 88, 1987,flerlal No. 2 155,758. Divided and this application filed Inch 88, 1828.

This invention relates to processes of oxidizing naphthalene tointermediate products, such as alphanaphjthaquinone, phtllalicanhydride, maleic acid, etc.

According to the present invention, naphthalene is oxidized,particularly in the vapor phase, in the presence of catalysts or contactmasses containing, when freshly prepared, zeolites which are thereaction products of lo at least three different classes of com onentsand which in the specification and claims will be referred to asmulti-component zeolites.

Some of the zeolites which are used in the new catalysts have beendescribed and is claimed products in'my application, Serial No. 142,783,filed October 19, 1926, now Patent No. 1,728,732, dated September17,1929, of

which the present application is in part a continuation.

Zeolite forming components may be divided into three classes :-silicateswith or without partial substitution of other suitable acidic oxides;metallates, such as alkali metal metallates; and salts of metals whichare sufiic5 ciently amphoteric to form base exchange bodies when causedto react with silicates under conditions suitable for the production ofzeolites. The ordinary zeolites of commerce are prepared by the reactionof a soluso le silicate, either with alkali metal metallates or withmetal salts. The catalysts of the present invention, on the other hand,are reaction products of a silicate with at least one metallate and atleast one metal salt. The present invention is directed to processes ofI oxidising naphthalene in the presence of such mnlticomponent zeolitesand their derivatires, in which at least one catalytically activeelement or radical is chemically combined with or in the zeolite. Bothdiluted and undiluted multi-component, zeolite catalysts can be used inthe present invention, but in many cases the use of dilutedmulti-component zeolites is preferable. In the diluted Zeolite contactmasses used in the present in caution, the catalytic power may residewholly in the zeolite or in chemical combination therewith, or it mayreside partly in the zeolite and partly in diluents combined therewithto "form mixtures or preferably physi- Serial No. 285,520.

diluents may be associated with catalytically ineffectivemulti-component zeolites, and

such processes are included within the scope of the present invention.

All of the base exchange bodies used in the present invention, bothdiluted and undiluted, possess a remarkably porous, honeycomb-likestructure, and are 111, many cases opalescent. When suitablecatalytically active components are present, they form catalysts orcontact masses of remarkable elliciency, due probably in part at leastto the extraordinarily high surface energy of the microscopically porousstructures, and probably also to the presence of unsaturated valences inmany cases and a symmetry of the molecules. It is of course possiblethat the catalytic activity} of the contact masses used in the presentinvention is due partly or wholly also to other reasons, and the present invention is therefore not intended in any sense to be limited toanytheory of action of the products. The molecular complexes which arepresent in the products used in the present invention are apparently ofgreat size and complexity, and the exact chemical constitution has notbeen determined, nor has it been determined definitely whether in allcases single chemical compounds are formed,

and it is possible that in some cases at least molecular mixtures orsolid solutions may be present. The products used possess a physicallymicroscopical homogeneity, and behave in many ways as if they weresingle compounds, or in the case of diluted zeolites, the zeoliteskeleton behaves as if it were a single compound, and I am of theopinion that probably in man cases at least the zeolites are actually inact single compounds of high molecular weight.

It should be understood that the products used in the present inventionare chemically quite distinct from zeolites formed by the reaction of asilicate with either metallates or with metal salts, the so-called twocoinponent zeolites.

The products used in the resent invention fall into three main types, eending on the relative proportions of the t rec classes of tlertaincompounds such as for example, vanadntes, molybdates, tungstutes,tantalates and uranates, which are not ordinarily considered asmetallates, but which are capable of forming; base exchange bodies withsoluble silicates and metal salts, are intended to be included under theterm metallates as used in the present invention. I therefore includeunder this term any alkali metal compound ot' a metal acid whiclriscapable of forming with soluble silicates and metal salts base exchangebodies, or which can be rendered capable of so reacting b a change ofvalence which can be effected uring the re notion. Thus for example,certain alkali pcrmangunates which are incapable of formmg base exchangebodies containing hept-avalent manganese may be caused to react withsoluble silicates and metal salts in the presence of suitable reducingagents which reduce the permanganate to a stage of oxidetion in which itis capable of behaving as a metallate. Such compounds are included undcrthe classification oi metallates for the purposes of the presentinvention, and some very valuable products can be produced by the use ofthis type of compound. An example of an important element which may beso,

used is tctruvulent vanadium. The present invention may utilize a.single metallatc component, or a plurality of metallntc components inany desired ratio may be used. The following elements are included amongthose forming metallates which can be uscd :-zilu1ninuni, chromium,zinc, vanadium. beryllium, tin, palladium, osmium, plat inum, titanium,zirconium, lead, tungsten, boron, molybdenum, uranium and tantalum,copper, nickel, iron, cobalt, silver, cadmium, manganese, bismuth,thorium, and cerium.

The metal salt components are likewise numerous, and in general, anywater-soluble, acid, neutral or basic salts or any mixtures till till

may be used. The following elements are included among those which formsuitable s;ilts:-coppcr, silver, gold, beryllium, zinc, cadmium,aluminum, rare earths, titanium, zirconium, tin, lead, thorium,chromium, uranium. vanadium, manganese, iron, nickel and cobalt.

The silicate component may be an alkali metal silicute or other silicatewhich is soluble in alkali or part of the silicate component may besubstituted in port by alkaline salts of the acids of thefollowing'elen1ents: boron, phosphorus, sulfur, nitrogen, tin, tcl--lurium. selenium, arsenic and antimony. All of these compounds arecapable of forming base exchange bodies with the other components. andare therefore to be considered the equivalent of the silicates.

The range of the new products used in the present invention is notlimited to the elenicnts present in the components which particularlyi'orm the non-exchangeable nucleus of the zeolite. On the contrary, itis possible to substitute the alkali metal ions by other metal cations.b means of base exchange.

Thus for examp e, one or more of the follow- .ing cations may beintroduced :-am1 no'nium,

copper, silver, gold, beryllium, magnesium,

calcium, zinc, strontium, cadmium, barium,

aluminum, thallium, titanium, zirconium, tin, thorium, vanadiumchromium, uranium, manganese, iron co alt, nickel, palladium, andplatinum. 'l he elements or radicals may be introduced as simple orcomplex ions, or both in any desired proportions. The introductlon canbe ell'ected simultaneously or successively. The number of possiblecombinations by means of base exchange is of course ver great, as willbe readily apparent to a zoo ite chemist. The number of new compounds istherefore greatly increased, and

many valuable products, particularly cata-.

lysts or activators can be produced by the introduction of suitablebase'exchange ions, which may increase the concentration of catalysts oractivators in the product, or may result in a more finely tunedcatalyst. The increase in catalytic activity which is frequentlypossible by a suitable introduction of the desired cations by baseexchange frequently increases the ermissible loading of the product innaphthalene oxidations and may increase resistance to high temperatures,the percents. e yield which can be obtained thereby, or the output, orboth.

A further series of catalysts can be obtained by treating the baseexchange bodies of the present invention with compounds containingsuitable acid radicals which form with the base exchange bodiessalt-like bodies. While these products behave in many ways as if thewere actual salts, the exact chemical constitution of the products isnot definitely known, and the invention is not intendedto be limited byany'theory as to compositions.

For the urposes of the present invention, acids or so ts of the followinelements may be used in order to produce sa t-like bodies vanadium,tungsten, uranium, chromium, molybdenum, manganese, selenium tellurium,arsenic, phosphorus, sulfur, chlorine, bromine, fiuorine,n1trogen andboron. 1mple acids or their salts can be utilized, or polyucids,peracids and complex ions may be substituted wherever this is desirable.

Other complex anions, such as form or ferrythis means salt-like baseexchange bodies having the characteristics of acid neutral or to orations under any particular pressure.

' SllC basic acid derivatives can be. roducegl. The diluted zeoliteswhich have found to be the most effective catalysts or contact massesfor the oxidation of naphthalene can.

be prepared in a 'numberof ways by the in as for example, ighly askieselguhr, g aucosi, .Celite? brick refuse, sil1cates,inact1vezeolites, pumicemeal,

and other products, or they may be coated onto natural and artificialmassive carrier fragments. The method of incorporatin and nature ofdiluents .which are to be used, has been described in detail 'in theco-pendin lication of Alphons OI Jaeger and a J d ann A. Bcrtsch, SerialNo. 95,771, filed March 18, 1926, where the incor oration of diluents intwo component zeo ites is described. While the resent products arechemically quite di erent from zeolites which are pre ared from twocomponents, the methods 0 precipitation are analogous.

I have found, therefore, that in most cases the same methods ofincorporating diluents which have been described in the priorapplication, above referred to, in connectionv with two componentzeolites, may be advantageously used for the incorporation of diluentsin basecxchan e bodies used in-the the invention is in no sense limitedto the details of the examples which are'illustrative modifications onlY The precipitation of the base exchange bodies is fre ueiitly slow, andsometimes incomplete, an it is often desirable to accelerate or completethe precipitation by heating vigorous stirring, or by the addition ofacids, either organic or inorganic, in H uid or gaseous form. Thus forexample, by rochloric acid,sulfuric acid,carbonic acid nitric acid,acetic acid, formic: acid and the like, or their acid salts, may beused. The addition of the acid is merely to decrease the excess ofalkali and, of course, is stop d before the reaction becomes acid to penolphthalein or litmus as .the case may be. Ammonium salts and salts ofthe alkalies as well as halogens, alcohols and other organic substances,

precipitation, and are included in the scope of the present invention.In some cases, it

is advantageous to operate under pressure in autoclavcs, and the presentinvention is therefore not limited in its broader. aspects corporationof a lar e variety of diluents,

porous diluents,--

. e important, property of porosity. of base exchange products-of theresent'invention may in manyl casesbeen anced by the i'ncorporationlwitthe bodies, during formation, of products which are readily removableeither by volatilization, combustionor by leaching, leaving behindadditional pores, and thus still furthercontributin to the permeabilityof the frameworkof t e base exchange products. The removable products tobe used may be inorganic ororganic, and

include a wide number of products, but the choice of products will ofcourse depend on t e characteristics of the base exchange body. heproduction, of base exchange bodies usually results in a considerablepercentage" of soluble salts in the reaction mixture, and

'chanical strength of the product, and may also desirabl afiect itschemical constitutioniparticu arly by changing its alkalinity 0racidity.

I find that it is often advantageous to subjectthe catalysts and contactmasses used in the present invention to a preliminary treatment,consisting, first, in a calcination in the presence of air or othergases as de scribed in my prior Patents Nos. 1,678,626 and 1,678,627,issued July 24, 1928.

This preliminary treatment or the catalytic processitself, which takesplace at high temperature, results in certain chemical changes in thecatalyst or contact mass which are not well defined and when thecatalyst is referred to in the claims, it should be considered as of thetime when it is freshly made, as is usual in catalytic chemicalnomenclature.

The oxidation of naphthalene requires a slowing down, or stabilizing, ofthe catalysts used, 1n order to prevent excessive losses through totalcombustion, or to permit stopping at a definite intermediate oxidationproduct with maxim-um yield. I have found that the presence of salts ofalkali-forming metals and other non-catalytic components may actasstabilizers, as may the oxides or hydroxides themselves in some cases.Where the stabilizers are oxides or hydroxides of the alkali-formingmetals the catalyst is treated by calcination with acid gases to preventthe presence of strong alkalies in the catalyst when it is used. Othercatal ically active or activating substances whic enhance theefiectiveness of the stabilizers,-and which are nuances termedstabilizer promoters, may be used. In fact whenever base exchangecatawhich act as stabilizers, and many of the amphoteric or other metalcomponents which n a" a. a l

are not selective catalysts for the oxidation of naphthalene may beconsidered, and act as stabilizer promoters. I do not claim in thisapplication the use of stabilizers or stabilizer promoters in general,as these form the subect-matter of my prior PatentNo. 1,709; 853, datedApril 23, 1929. The expressions stabilizers and stabilizer promoters,when used in the present application, are to be understood as used inthe sense in which they are defined in the aforementioned copendingapplication. It should be understood that while many of the multi-compoment zeolite catalysts used in the present invention ma be considered ascomposite stabilizers an stabilizer promoters, the invention is notlimited thereto, and stabilizers or stabilizer promoters, or. both, maybe separately added to the catalysts of the present invention, and infact many of the dlluents, ior example those containing certain heavy oramphoteric metal compounds are to be considered as stabilizer promoters.

detail in connection with the following speciiic examples which areillustrative merely,

tilt

and do not limit the broader scope of the in uention. The examples,however, do in many cases contain specific features which in their morenarrow aspects are included in the present invention. The examples givea few typical reaction conditions and catalysts, but it should beunderstood that the skilled catalytic chemist will choose within theconfines oi the present invention. catalysts and reaction conditionsbest suited to the particular reaction in which he is interested.

Example 1 l6 parts of vanadic acid are formed into a slurry with 300parts of water and are acidified with sulfuric acid. The mixture isthen. heated to boiling and a rapid stream of sulfur dioxide is passedthrough the hot solution; in a short time, a blue solution of vanadylsulfate is formed. After boiling out the excess sulfur dioxide, the bluesolution is divided into two portions in the ratio of 52: 3. B/bths ofthe blue solution are cautiously treated with a concentrated causticpotash solution until a clear brown solution of potassium vanadite isformed. 140 parts of potassium waterglass of 39 B. are diluted with 500parts of water and the potassium vanadite is poured in with vigorousstirring. Into the mixture are stirred -80 parts of Benito brick refuse.The mixture is then gently warmed and the remaininglg/fiths'of thevanadyl sulfate is added in a t in stream with vi rous agitation, whereun the mass first solidifies to a-graty-green ge and on fur- Q therstirring istrans ormed into readily filterable granular ag egates.

The amount of a li used in the solutions should be so chosen so that atthe endofthe reaction the mixture remainsweakl alkaline or neutral tophenolphtha'lein. f the alkalinit-y of the reaction mixture is muchgreater, the precipitation is delayed but can be accelerated by theaddition. of 7 about 50 parts of a saturated potassium sulfate solutionwhich, by its salting out efiect, improves the yield.

Another method of accelerating preoipita tion is to reduce thealkalinity of the reaction mixture by cautious addition of diluteacidsor solutions of acid salts, such as for example, hydrochloric acid,sulphuric acid, potas sium bisulfate, and the like. By this means anydesired degree of alkalinity or neutrality of the resulting reactionproduct can be easily obtained- The reaction mixture is allowed to standand is then decanted, pressed and washed with water. The press-cake isdried preferably below C. and the three component base exchange bodycontaining SO; and] 1 V 0 is then broken into fragments or is Theinvention willbe described in greater hydrated with water in which caseit also light gray, hard body having cone. oidal fracture and p baseexchange properties. The base, exchange body may be dehydrated byheating in a streamof hot air and Ewtzmple 9 Y Three mixtures areprepared as follows:

(1) 210 to 250 parts of sodium waterglass solution 33 B6. diluted with15 to 20 volumesof water are mixed potassium or -breaks into granules.The final roduct is a I i treatment, is filled into a conwith kieselguhror other material richin Si0 such as glaucosil, the acid treated residueof greensand, until a suspension is obtained which is just stirable.

, 2) 18 parts of V,(), are dissolved in just sufiicient 10-20% causticpotash or caustic soda solution so that potassium or sodium vanadate isobtained.

(3) 18 parts of V 0 are reduced with sulphur dioxide in aqueoussuspension in the usual way to form the blue vanadyl sulfate about 200to 300 parts of water being needed. The excess S0, is removed byboiling.

Mixtures (1) and (2) are poured together and solution (3) is permittedto flow in with vigorous agitation, taking care that the reac with alittle water and then dried and constitutes a three component baseexchange body containing tctravalent and pentavalent vanadium innon-excha able form and having materials rich in Si finely distributedthroughout its framework.

The contact-mass,'before use, is treated at 400 to 500 C. with about 3%burner gases and the product obtained becomes an excellent contact massfor the catalytic oxidation of naphthalene to alphanaphthaquinone,phthalic anhydride and maleic acid under conditions suitable for each ofthese reaction products. Among these conditions ma be mentionedtemperature at which thecata ytic oxidation of naphthalene is carriedout, the time of the reaction, mixture of naphthalene and air, theproportion of the catalyst to the reactin gases and the relativeproportions of nap thalene and oxygen to the diluent gases such ascarbon dioxide and nitrogen.

Naphthalene and air mixed in the ratio of 1: 16 are passed over thecontact mass at 380'to 420 C. and produce phthalic anhydride.Naphthalene and air mixed in the ratio of 1:40 when assed over thecontact mass at 360 to 390? produce lar e amounts of a1 hanaphthaquinonein a dition to phthahc anhydride. When temperatures of 420 to 500 C. areused in the manufacture of hthalic anhydride, the phthalic anhydridecontains considerable amounts of maleic ac1 A further improvement ofthese contact masses for several specific catalytic oxidation reactionscan be effected by forming salt-like bodies of the three component baseexchange body with acids of the elements of the 5th and 6th group of theperiodic system, especially vanadium, tungsten, and molybdenum.

A further modified method of preparing highly eflicient contact massesconsists in introducing in the diluents, before use, yanadatesmolybdates, tungstates, chromates or tantal For this pur the diluentsmay be impregnated wi 3 to 5% of such metallates in the usual waywhereby veryefl'ective catal for the catalytic oxidations of many of t eaforesaid'hydrocarbons are obtained.

E'mmple 3 Three mixtures are prepared as follows:

1 1) 910 arts of gratessium waterglass solution of a out 33 diluted with6-8 volumesof water are mixed with amixture of comminuted silicates andkieselguhr until the suspension remains easily stirrablc. The

ates, especially of the heavy metals.-

mixed diluent of silicates and kieselguhr contains fireferably more than25% of kieselguhr. e limits for the addition of the amount of diluentscan be chosen throughout lar range without afiecting the catalytic eciency of the final product to any great extent. V

(2) 18 parts of V,O, are reduced in a hot aqueous solution acidifiedwith H 80, to a blue vanadyl sulphate solution by means of sulphurdioxide and the vanadyl sulphate obtained is transformed into a brownsolution of potassium vanadite by treatment with sufiicient 10 N.caustic potash solution in the usual way.

(3) A sufiicient amount of 10% aluminum sul hate solution is prepared.

uspension (1) and solution (2) are poured result.

Solutions (2) can substituted in part or in whole by corres ding amountof potassium vanadate solution dissolvin the V 05, without reduction,directly in 2 potassium hydroxide. In this case a gel is produced whichcontains V,O4 and 7,0,, A1 0, and SiO, corresponding to the threeclasses of components used in the initial solutions.

The solution 3 can also be substituted in part or in whole by othermetal salt solutions.

such as, for example, copper sulphate, nickel sulphate, cobalt sulphate,iron sulphate, manganese nitrate, ferric chloride and the like, singlyand in admixture.

The bodies can also be changed after drying preferably at 100 C. by baseexchange or by the formation of salt-like bodies, whereby the brokenbase exchange body is first hydrated by trickling water over it. I

The base exchange bodies are transformed to salt-like bodies by sprayinga diluted H,SO, and HNO. over themass or by heating the mass to 420 to500 C. and passing 3 to 5% burner gases over it, and are very efiicientcontact mamas for the catalytic oxi-' all! till

till

Example 4 12 parts of V 0 are suspended in 300 parts of water to form aslurry, acidified with 3 to 8 parts of concentrated sulphuric acid andthen reduced tothe blue vanadyl sulphate by well known reducing meansas, for example, by means of. gases containing S0 which are passed inthe solution at the boiling temperature.

lOS-parts of waterglass solution of 33 B6. are diluted with 400 parts ofwater andabout to 100 parts of Celite brick refuse are stirred in.

The water-glass solution is then poured into the vanadyl sulphatesolution with vigorous agitation precipitating out vanadyl silicatediluted with Celite brick refuse. Care should be taken that after allthe solutions have reacted the resultingmixture must be neutral tolitmus, which can be adiustcdwith thedhelp of small amounts of N.sulphuric aci lliO parts of potassium water-glass solution of 33 B. arediluted with 300 parts of water.

6 parts of VA), are transformed with the help of NKO'H solution topotassium metaranadate and the waterglass solution and .yanadatesolution are mixed together.

40 parts of Al (S0,), 18 aq. are dissolved in 250 parts of water.

To this latter solution the ground, dilute rauadyl silicate is addedwith vigorous agitation in order tohrinq it in a suspension, then themixture of the two solutions of Wa'terglass and vanadate are added in athin stream with vigorous agitation.

The reaction mixture after the addition of the mixed solutions must beneutral or alkaline to phenolphthalein and the desired neutrality oralkalinity can easily be ad-,

iusted by using": corresponding amounts of N. sulphuric acid withvigorous agitation. The reaction mixture is separated from the motherliquor in the usual way and washed with twice the amount of the motherliquor obtained, dried and broken in suitable pieces. In order to usethis contact mass for the catalytic oxidation of naphthalene toalphanaphthaquinone and phthalic anhydride it is preferable to treat thecalcined contact mass with about 3% diluted SO -containing gases at 450to 500 C. the S0 being transformed into S0 and the latter neutralizingthe alkali content of the base exchange body.

Naphthalene mixed with air in the ratio of 3 .220 is passed over thiscontact mass, and gives excellent yields of phthalic anhydride at 370 to420 C. If the amount of air is largely increased, considerable amountsof alphanaphthaquinone are obtained in addition to phthalic anhydride.

Instead of using a potassium vanadate solution as the metallatecomponent other catalyticall active metallates, such as, tungstates andmo ybdates, may be used.

Instead of using an aluminum sulphate solution as the metal saltcomponent other metal salts, such as those of iron, copper, silver,nickel, cadmium, titanium, zirconium and chromium may be used singly orin admixture contact nasses with specific elliciency for other oxidationreactions being produced.

' Ewample 5 A mixture of 10 parts of V 0 and 4 parts of ,VVO, aredissolved in 300 parts of diluted KOH. solution containing about 10.5parts of %,KOH. To ,this solution about 90 using 2 N. sulphuric acid inorder to precipitate out V 0 and W0 in this diluent, or, in the mixtureof the diluents. The mixture obtained is then dried and ground. 40partsof 33 B. potassium waterglass solution are weighed out.

2 parts of A1 0 are transformed to the corresponding potassium aluminatein the usual way with the help of 5 N. potassium hydroxide solution.

The two solutions are then mixed together and. immediately after mixing,kneaded thorcughly with the V 0 and W0, precipitate and then formed intosuitable pieces. These formed pieces are then dried at temperaturesunder C. preferably with gases containing CO whereby a diluted threecomponent base exchange body is obtained containing V 0 W0 A1203 and SiOin non-exchangeable form. The contact mass so obtained is calcined with3 to 6% S0 gases containing a sufiicient amount of' oxygen, first atroom temperature and then at 450 to 500 C.

This contact mass is well suited for the catalytic oxidation ofnaphthalene to phthal c anhydride, when naphthalene vapors and air atvarious ratios, such as, 1: 18 by weight, are passed over the catalystat 380 to 400 whereby high percentage yields of phthahc anhydride areobtained. Instead of usmg V 0 and W0, other catalytically effectivecomponents such as those containing metal elements of the 4th and 6thgroups of the periodic system may housed in the same way to produceanalogous products. Examples of such components are V 0 M00 Te l), andU0 they may be used. singly or in admixture, with or without/V 0, and W03 Instead of using potassium aluminate other metallates of elementswith amphoteric prop lOti by adding N tains vanadium, copper,,aluminumierties can be used, such as, cadmium, beryllium, and zinc.

Example 6 (l) 20 parts o V 0, are dissol n 150 to 200 parts of watercontaining about 17 parts of 90% KOH.

(2) 6 parts of CuSO, 5 aq. are dissolved in 150 to 200 parts of waterand concentrated ammonia solution is added until a clear blue solutionof cuprammonium complex is obtained.

(3) 2 arts of freshly precipitated A1 0, are disso ved in thecorresponding amount of 2N.KOH solution in order to form potassiumaluminate.

(4 parts of potassium waterglass of 33 are diluted with twice the amountof water and of 10% ammonia is added until the cloudy precipitate firstobtained is again dissolved.

5) 42 parts of Fe (SO.) plus 9 aq. are dissolved in 200 parts of water.

The aluminate and cuprammonium complex solutions are poured together and80 to parts of unground infusorial earth are added in order to form asuspension of the diluent with the mixture. The mixture of the vanadateand waterglass solution are then added with vigorous agitation and theferri-sulhate solution is poured in a thin stream.

he reaction mixture remains alkaline to phenolphthalein and can beadjusted to neutrality or sli ht alkalinity to phenolphthalein 51 80 Theproduct so obtained is freed from the mother liquor by filtering andpressing and is washed out with about 300 parts of water in portions.The presscake is then dried at temperatures preferably below C. andbroken into small fragments. The three component zeolite obtainedconiron, and SiO, in non-exchan able form di uted with ungroundinfusoriafzarth. Before use, this contact mass is calcined with air at400 C. in order to deh drate the mass.

After a preiminary treatment with diluted burner at about 450 the massobtained is wel suited for the catalytic oxidation of naphthalene tophthalicanhydride.

- Naphthalene vapors mixed with air in .varithe time when it is freshous ratios, such as 1:16 are assed over the contact mass at 380 to 400whereby high percentage yields are obtained.

In the claims the catalyst is defined as of y prep md. rCal- 'cinationwith or without acid gases or the conditions of the catalytic reactionitself will remove the base exchanging power of the multi-componentzeolite either y dehyration or chemical reaction. It should beunderstood that the claims are intended to define the catalyst as of thetime when freshly prepared, but

of course the claims do not include catalysts which have been subjectedto subsequent chemical treatment other than calcination with or withoutacid gases as described in the specification.

TlllS application is a division of my application Serial No. 215,759,filed August 26,

to react'with an oxidizing gas in the presence of a contactmasscontaining at least one compound selected from the group consistingof zeolites which are the reaction products of a soluble silicate withatleast one metallate and at least one salt, the positive acting radicalof which contains a metal capable of entering into the non-exchangeableportion of a zeolite molecule and salt-like derivatives of such zeolitesby reaction with an anion capable of forming salt-like bodies therewith.

2. A method of oxidizing naphthalene to intermediate products whichcomprises vaporizing na hthalene and causing the vapors to react wit anoxidizing gas in the presence of a contact mass containing at least onecompound selected from the group consisting of diluted zeolites whichare the reaction products of a soluble silicate with at least onemetallate and at least one salt, the positive actlng radical of whichcontains a metal capable of entering into the non-exchangeable portionof a zeolite molecule and salt-like derivatives of said diluted zeolitesby reaction with an anion capable of forming salt-like bodies therewith.

3. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing na hthalene and causing the vapors to react wit anoxidizing gas in the presence of a contact mass containing at least onecompound selected from the group consisting of zeolites which are thereaction products of a soluble silicate with at least one metallate andat lead one salt the pomtive acting radical of which contains a metalcapable of en tering into the non-exchangeable portion of a zeolitemolecule and salt-like derivatives of such zeolites by reaction with ananion capable of formin' salt-like bodies therewith, at least one ca thecontact mass being chemically combined with the zeolite.

4. A method of oxidizing naphthalene to intermediate ytically activecomponent of roducts, which com vaporizing napt alone and causing evapors to react with an oxidizing gas in the presence of a contact masscontaining at least cm lite which is the reaction p' on amfluble,

silicate with at least one new." one salt, the positive act I tablet-d;

non-exchangeable portion of see to male i contains mew F 0 enteringvinto the tilt tltt

tlitll cule, at least one catalytically active component of the contactmass being chemically combined with the zeolite in non-exchangeableform.

5. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors x to reactwithan oxidizing gas in the presence of a contact mass containing at leastone diluted zeolite which is the reaction product of a soluble silicatewith at least one metallate and at least one salt, the positive actingradical of which contains a metal capable of entering" into thenon-exchangeableportion of a zeolite molecule, at least onecatalytically etztective component of the contact mass being physicallyassociated with the zeolite in the form of a diluent.

6. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence of a contact mass containing at least onezeolite which IS the reaction product of a soluble silicate with atleast one metallate and at least one salt, the positive acting radicalof which contains a metal capable of entering into the non-exchangeableportion of a zeolite molecule in which chemically combined vanadium ispresent.

7. A method of oxidizing naphthalene to intermediate products, whichcomprises vaporizing naphthalene and causing the vapors to react with anoxidizing gas in the presence ol :1 contact mass containing at least onediluted zeolite which is the reaction product of a soluble silicate withat least one metallate and at least one salt, the positive actingradical oil which contains a metal capable of entering into thenon-exchangeable portion of a aeolite molecule, at least part of thediluents containing vanadium compounds.

higned at Pittsburgh, Pennsylvania, this Hist day of March, 1928 ALPHUNSU. JAEGrER,

